OK, after i put on my header my car was fine. After a few weeks i heard rattling noise so i jack up the car and look. Some bolts was loose around the cat so i tighten them. The rattling noise got softer but it's still there. It start rattling around 2500-4000rpm, could it be a sign of the cat broken? If so, what kinda of cat do you guy recommend? Thanks....

Oh, it's a random cat...

 

my noise is coming from my resonater, you should have it checked out at an exhaust place.

 

I had this problem with one of my other cars, ur saying its a soft rattling noise, like a loose bolt. let ur gas tank go nearly empty then fill it with premium gas (91 or 94 octane) drive it and see if the noise goes away. If it does then u got work that needs to be dun with the motor, or jus keep putting in premium fuel.

 

Huh? How does that work?

Did you tighten up your bolts properly? Maybe your cat heat shield is rusted through.

 

I don't think he has a problem with his motor, but rather a heat shield or something is loose.

 

If its right around the cat its probably the heat shield around the cat like someone else said or the brick inside the cat is loose and rattling around. Take it off and shake to see if its loose.

 

had that problem, drove around like that for a bit and was so annoyed. Ended up being the heatshield but the cat, the bolt hole broke, so it was slightly suspened but still rubbing against the cat. so i just too off the heatshield and that solved the problem.

 

If it's the heat shield, what can i do to fix it? or do I have to buy a new cat? And what cat do you guy recommend?

 

I had the same problem and it was the heatshield being loose. I just took it off and been driving without it for awhile..

 

the pieces inside your cat are probably broken. take it off and shake it to see if anything falls out. I have seen people take the cat of and finish breaking everything inside of it. Basicaly cleaning it out.

 

is it ok to drive around without a heatshield?

 

Yeah it is okay to drive around with no heat sheild, Just dont park on any tall dry grass because it may catch it on fire. Just rip the heat shield off, I am 99.9% sure that is your rattling problem.

 

That is just useless JUNK, take it off and call it a day.

 

Heatshields? Well, if it's 100 degrees out and you're idling in traffic, they're there to keep the underbody spray from melting off and maybe even to stop the carpet from catching on fire

 

Never even heard of it happening.

 

ok i guess ill try taking my heatshield out. The guy at the exhaust place said that it was my resonator that was making the noise.... maybe he's just pulling my leg Im gonna work on my car tomorrow so ill check the heatshield, thatll save me about $100 on the resonator

 

How do you guy take off the heat shield? I dont see how i can do that.

 

check to see if your header is ratteling against your oil pan

i was chasing "loose bolts" for ever untill i realized this. dunno what im going to do to fix it.